Introducing the brain: vagus nerve and immunity (Introduction)

by David Turell , Monday, April 29, 2024, 16:18 (206 days ago) @ David Turell

Can suppress immunity:

https://mail.google.com/mail/u/0/#inbox/FMfcgzGxStwKpkRXmcSZWXbHsVzWSzMM

"The long, wandering nerve at the center of the gut-brain axis can play havoc with the immune system.

"The vagus nerve, which takes a meandering path from the base of your brain to your internal organs and back again, plays a vital—and somewhat mysterious—role in the so-called “gut-brain connection.” The twisting branches of this 100,000-fiber network are known to influence digestion, blood pressure, and even memory and mood —offering a tantalizing target for the treatment of conditions like obesity and depression.

"In recent years, scientists have also sought to unravel the link between the vagus nerve and immunity. As previous studies have shown, stimulating this nerve triggers the release of a neurotransmitter called acetylcholine, which dampens the activity of immune cells in the spleen. While this suppression can help shield organs from inflammation, especially during cases of acute sepsis, it may also cause long-term issues. Now, new experiments in mice demonstrate that chronic stimulation of the vagus nerve can impair the function of “boot camps” known as germinal centers, which temporarily form in the lymph nodes and spleen during infection.

"In healthy rodents, these structures help certain immune cells learn how to produce antibodies. But when researchers continuously activated an animal’s vagus nerve with electrodes, its germinal centers exhibited altered gene expression—stunting the growth of immune cells and impairing their ability to recognize harmful pathogens."

Comment: the vagus is a master nerve affecting all the bodily organs. For example, a vaso-vagal effect can drop the blood pressure and slow the heart all at once. This demonstrated suppressing effect on the immune system is confusing. Is it a protection from autoimmune reactions? We don't clearly see purpose.